Bicyclic inhibitors of histone deacetylase

ABSTRACT

Provided herein are compounds and pharmaceutically acceptable salts thereof, and pharmaceutical compositions thereof, which are useful in the treatment of conditions associated with inhibition of HDAC (e.g. HDAC2).

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/541,807 filed Aug. 7, 2017, the contents of which are incorporatedherein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

This invention was made with government support under Small BusinessInnovation Research (SBIR) grant 1R43AG048651-01A1 awarded by theNational Institute of Health (NIH). The government has certain rights inthe invention.

BACKGROUND

Inhibitors of histone deacetylases (HDAC) have been shown to modulatetranscription and to induce cell growth arrest, differentiation andapoptosis. HDAC inhibitors also enhance the cytotoxic effects oftherapeutic agents used in cancer treatment, including radiation andchemotherapeutic drugs. Marks, P., Rifkind, R. A., Richon, V. M.,Breslow, R., Miller, T., Kelly, W. K. Histone deacetylases and cancer:causes and therapies. Nat Rev Cancer, 1, 194-202, (2001); and Marks, P.A., Richon, V. M., Miller, T., Kelly, W. K. Histone deacetylaseinhibitors. Adv Cancer Res, 91, 137-168, (2004). Moreover, recentevidence indicates that transcriptional dysregulation may contribute tothe molecular pathogenesis of certain neurodegenerative disorders, suchas Huntington's disease, spinal muscular atrophy, amyotropic lateralsclerosis, and ischemia. Langley, B., Gensert, J. M., Beal, M. F.,Ratan, R. R. Remodeling chromatin and stress resistance in the centralnervous system: histone deacetylase inhibitors as novel and broadlyeffective neuroprotective agents. Curr Drug Targets CNS Neurol Disord,4, 41-50, (2005). A recent review has summarized the evidence thataberrant histone acetyltransferase (HAT) and histone deacetylases (HDAC)activity may represent a common underlying mechanism contributing toneurodegeneration. Moreover, using a mouse model of depression, Nestlerhas recently highlighted the therapeutic potential of histonedeacetylation inhibitors (HDAC5) in depression. Tsankova, N. M., Berton,O., Renthal, W., Kumar, A., Neve, R. L., Nestler, E. J. Sustainedhippocampal chromatin regulation in a mouse model of depression andantidepressant action. Nat Neurosci, 9, 519-525, (2006).

There are 18 known human histone deacetylases, grouped into four classesbased on the structure of their accessory domains. Class I includesHDAC1, HDAC2, HDAC3, and HDAC8 and has homology to yeast RPD3. HDAC4,HDAC5, HDAC7, and HDAC9 belong to class IIa and have homology to yeast.HDAC6 and HDAC10 contain two catalytic sites and are classified as classIIb. Class III (the sirtuins) includes SIRT1, SIRT2, SIRT3, SIRT4,SIRT5, SIRT6, and SIRT7. HDAC11 is another recently identified member ofthe HDAC family and has conserved residues in its catalytic center thatare shared by both class I and class II deacetylases and is sometimesplaced in class IV.

In contrast, HDACs have been shown to be powerful negative regulators oflong-term memory processes. Nonspecific HDAC inhibitors enhance synapticplasticity as well as long-term memory (Levenson et al., 2004, J. Biol.Chem. 279:40545-40559; Lattal et al., 2007, Behav Neurosci121:1125-1131; Vecsey et al., 2007, J. Neurosci 27:6128; Bredy, 2008,Learn Mem 15:460-467; Guan et al., 2009, Nature 459:55-60; Malvaez etal., 2010, Biol. Psychiatry 67:36-43; Roozendaal et al., 2010, J.Neurosci. 30:5037-5046). For example, HDAC inhibition can transform alearning event that does not lead to long-term memory into a learningevent that does result in significant long-term memory (Stefanko et al.,2009, Proc. Natl. Acad. Sci. USA 106:9447-9452). Furthermore, HDACinhibition can also generate a form of long-term memory that persistsbeyond the point at which normal memory fails. HDAC inhibitors have beenshown to ameliorate cognitive deficits in genetic models of Alzheimer'sdisease (Fischer et al., 2007, Nature 447:178-182; Kilgore et al., 2010,Neuropsychopharmacology 35:870-880). These demonstrations suggest thatmodulating memory via HDAC inhibition has considerable therapeuticpotential for many memory and cognitive disorders.

Currently, the role of individual HDACs in long-term memory has beenexplored in two recent studies. Kilgore et al. 2010,Neuropsychopharmacology 35:870-880 revealed that nonspecific HDACinhibitors, such as sodium butyrate, inhibit class I HDACs (HDAC1,HDAC2, HDAC3, HDAC8) with little effect on the class IIa HDAC familymembers (HDAC4, HDAC5, HDAC7, HDAC9). This suggests that inhibition ofclass I HDACs may be critical for the enhancement of cognition observedin many studies. Indeed, forebrain and neuron specific over expressionof HDAC2, but not HDAC1, decreased dendritic spine density, synapticdensity, synaptic plasticity and memory formation (Guan et al., 2009,Nature, 459:55-60). In contrast, HDAC2 knockout mice exhibited increasedsynaptic density, increased synaptic plasticity and increased dendriticdensity in neurons. These HDAC2 deficient mice also exhibited enhancedlearning and memory in a battery of learning behavioral paradigms. Thiswork demonstrates that HDAC2 is a key regulator of synaptogenesis andsynaptic plasticity. Additionally, Guan et al. showed that chronictreatment of mice with SAHA (an HDAC 1,2,3,6, 8 inhibitor) reproducedthe effects seen in the HDAC2 deficient mice and recused the cognitiveimpairment in the HDAC2 overexpression mice.

The inhibition of the HDAC2 (selectively or in combination withinhibition of other class I HDACs) is an attractive therapeutic target.Such inhibition has the potential for enhancing cognition andfacilitating the learning process through increasing synaptic anddendritic density in neuronal cell populations. In addition, inhibitionof HDAC2 may also be therapeutically useful in treating a wide varietyof other diseases and disorders.

SUMMARY

Disclosed are compounds and pharmaceutically acceptable salts thereof,and pharmaceutical compositions, which are useful in the treatment ofconditions associated with the activity of HDAC (e.g., HDAC2). See e.g.,Table 1.

One of the advantages of certain compounds described herein is that theypossess enhanced safety parameters. For example, the inclusion of anadditional fluorine atom on the bottom phenyl ring of certain compoundsprovided almost a 2-fold increase in safety, showing fewer effects onhuman erythroid and myeloid progenitors. See e.g., Table 4, Comparator 1vs Compound 10; Comparator 2 vs. Compound 3; Comparator 5 vs. Compound1; and Comparator 6 vs. Compound 2. A similar result was seen betweenregioisomers (compare Comparator 4 with Compound 8) and the replacementof hydrogen for fluorine (compare Comparator 3 with Compound 6).

Conditions which are treatable by the disclosed compounds include, butare not limited to, neurological disorders, memory or cognitive functiondisorders or impairments, extinction learning disorders, fungal diseasesor infections, inflammatory diseases, hematological diseases, neoplasticdiseases, psychiatric disorders, and memory loss.

DETAILED DESCRIPTION 1. Compounds

Provided herein are compounds having the formula selected from:

or a pharmaceutically acceptable salt thereof.

Other examples of compounds included in the present disclosure areprovided in the EXEMPLIFICATION section. Pharmaceutically acceptablesalts as well as the neutral forms of these compounds are included.

2. Definitions

As used herein the terms “subject” and “patient” may be usedinterchangeably, and means a mammal in need of treatment, e.g.,companion animals (e.g., dogs, cats, and the like), farm animals (e.g.,cows, pigs, horses, sheep, goats and the like) and laboratory animals(e.g., rats, mice, guinea pigs and the like). Typically, the subject isa human in need of treatment.

Pharmaceutically acceptable salts as well as the neutral forms of thecompounds described herein are included. For use in medicines, the saltsof the compounds refer to non-toxic “pharmaceutically acceptable salts.”Pharmaceutically acceptable salt forms include pharmaceuticallyacceptable acidic/anionic or basic/cationic salts. Pharmaceuticallyacceptable basic/cationic salts include, the sodium, potassium, calcium,magnesium, diethanolamine, n-methyl-D-glucamine, L-lysine, L-arginine,ammonium, ethanolamine, piperazine and triethanolamine salts.Pharmaceutically acceptable acidic/anionic salts include, e.g., theacetate, benzenesulfonate, benzoate, bicarbonate, bitartrate, carbonate,citrate, dihydrochloride, gluconate, glutamate, glycollylarsanilate,hexylresorcinate, hydrobromide, hydrochloride, malate, maleate,malonate, mesylate, nitrate, salicylate, stearate, succinate, sulfate,tartrate, and tosylate.

The term “pharmaceutically acceptable carrier” refers to a non-toxiccarrier, adjuvant, or vehicle that does not destroy the pharmacologicalactivity of the compound with which it is formulated. Pharmaceuticallyacceptable carriers, adjuvants or vehicles that may be used in thecompositions described herein include, but are not limited to, ionexchangers, alumina, aluminum stearate, lecithin, serum proteins, suchas human serum albumin, buffer substances such as phosphates, glycine,sorbic acid, potassium sorbate, partial glyceride mixtures of saturatedvegetable fatty acids, water, salts or electrolytes, such as protaminesulfate, disodium hydrogen phosphate, potassium hydrogen phosphate,sodium chloride, zinc salts, colloidal silica, magnesium trisilicate,polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol,sodium carboxymethylcellulose, polyacrylates, waxes,polyethylene-polyoxypropylene-block polymers, polyethylene glycol andwool fat.

The terms “treatment,” “treat,” and “treating” refer to reversing,alleviating, reducing the likelihood of developing, or inhibiting theprogress of a disease or disorder, or one or more symptoms thereof, asdescribed herein. In some embodiments, treatment may be administeredafter one or more symptoms have developed, i.e., therapeutic treatment.In other embodiments, treatment may be administered in the absence ofsymptoms. For example, treatment may be administered to a susceptibleindividual prior to the onset of symptoms (e.g., in light of a historyof symptoms and/or in light of genetic or other susceptibility factors),i.e., prophylactic treatment. Treatment may also be continued aftersymptoms have resolved, for example to prevent or delay theirrecurrence.

The term “effective amount” or “therapeutically effective amount”includes an amount of a compound described herein that will elicit abiological or medical response of a subject e.g., between 0.01-100 mg/kgbody weight/day of the provided compound, such as e.g., 0.1-100 mg/kgbody weight/day.

3. Uses, Formulation and Administration

In some embodiments, compounds and compositions described herein areuseful in treating conditions associated with the activity of HDAC. Suchconditions include for example, those described below.

Recent reports have detailed the importance of histone acetylation incentral nervous system (“CNS’) functions such as neuronaldifferentiation, memory formation, drug addiction, and depression(Citrome, Psychopharmacol. Bull. 2003, 37, Suppl. 2, 74-88; Johannessen,CNS Drug Rev. 2003, 9, 199-216; Tsankova et al., 2006, Nat. Neurosci. 9,519-525). Thus, in one aspect, the provided compounds and compositionsmay be useful in treating a neurological disorder. Examples ofneurological disorders include: (i) chronic neurodegenerative diseasessuch as familial and sporadic amyotrophic lateral sclerosis (FALS andALS, respectively), familial and sporadic Parkinson's disease,Huntington's disease, familial and sporadic Alzheimer's disease,multiple sclerosis, muscular dystrophy, olivopontocerebellar atrophy,multiple system atrophy, Wilson's disease, progressive supranuclearpalsy, diffuse Lewy body disease, corticodentatonigral degeneration,progressive familial myoclonic epilepsy, strionigral degeneration,torsion dystonia, familial tremor, Down's Syndrome, Gilles de laTourette syndrome, Hallervorden-Spatz disease, diabetic peripheralneuropathy, dementia pugilistica, AIDS Dementia, age related dementia,age associated memory impairment, and amyloidosis-relatedneurodegenerative diseases such as those caused by the prion protein(PrP) which is associated with transmissible spongiform encephalopathy(Creutzfeldt-Jakob disease, Gerstmann-Straussler-Scheinker syndrome,scrapic, and kuru), and those caused by excess cystatin C accumulation(hereditary cystatin C angiopathy); and (ii) acute neurodegenerativedisorders such as traumatic brain injury (e.g., surgery-related braininjury), cerebral edema, peripheral nerve damage, spinal cord injury,Leigh's disease, Guillain-Barre syndrome, lysosomal storage disorderssuch as lipofuscinosis, Alper's disease, restless leg syndrome, vertigoas result of CNS degeneration; pathologies arising with chronic alcoholor drug abuse including, for example, the degeneration of neurons inlocus coeruleus and cerebellum, drug-induced movement disorders;pathologies arising with aging including degeneration of cerebellarneurons and cortical neurons leading to cognitive and motor impairments;and pathologies arising with chronic amphetamine abuse to includingdegeneration of basal ganglia neurons leading to motor impairments;pathological changes resulting from focal trauma such as stroke, focalischemia, vascular insufficiency, hypoxic-ischemic encephalopathy,hyperglycemia, hypoglycemia or direct trauma; pathologies arising as anegative side-effect of therapeutic drugs and treatments (e.g.,degeneration of cingulate and entorhinal cortex neurons in response toanticonvulsant doses of antagonists of the NMDA class of glutamatereceptor) and Wernicke-Korsakoff's related dementia. Neurologicaldisorders affecting sensory neurons include Friedreich's ataxia,diabetes, peripheral neuropathy, and retinal neuronal degeneration.Other neurological disorders include nerve injury or trauma associatedwith spinal cord injury. Neurological disorders of limbic and corticalsystems include cerebral amyloidosis, Pick's atrophy, and Rettssyndrome. In another aspect, neurological disorders include disorders ofmood, such as affective disorders and anxiety; disorders of socialbehavior, such as character defects and personality disorders; disordersof learning, memory, and intelligence, such as mental retardation anddementia. Thus, in one aspect the disclosed compounds and compositionsmay be useful in treating schizophrenia, delirium, attention deficitdisorder (ADD), schizoaffective disorder, Alzheimer's disease,Rubinstein-Taybi syndrome, depression, mania, attention deficitdisorders, drug addiction, dementia, agitation, apathy, anxiety,psychoses, personality disorders, bipolar disorders, unipolar affectivedisorder, obsessive-compulsive disorders, eating disorders,post-traumatic stress disorders, irritability, adolescent conductdisorder and disinhibition.

Transcription is thought to be a key step for long-term memory processes(Alberini, 2009, Physiol. Rev. 89, 121-145). Transcription is promotedby specific chromatin modifications, such as histone acetylation, whichmodulate histone—DNA interactions (Kouzarides, 2007, Cell, 128:693-705).Modifying enzymes, such as histone acetyltransferases (HATs) and histonedeacetylases (HDACs), regulate the state of acetylation on histonetails. In general, histone acetylation promotes gene expression, whereashistone deacetylation leads to gene silencing. Numerous studies haveshown that a potent HAT, cAMP response element-binding protein(CREB)-binding protein (CBP), is necessary for long-lasting forms ofsynaptic plasticity and long term memory (for review, see Barrett, 2008,Learn Mem 15:460-467). Thus, in one aspect, the provided compounds andcompositions may be useful for promoting cognitive function andenhancing learning and memory formation.

The compounds and compositions described herein may also be used fortreating fungal diseases or infections.

In another aspect, the compounds and compositions described herein maybe used for treating inflammatory diseases such as stroke, rheumatoidarthritis, lupus erythematosus, ulcerative colitis and traumatic braininjuries (Leoni et al., PNAS, 99(5); 2995-3000(2002); Suuronen et al. J.Neurochem. 87; 407-416 (2003) and Drug Discovery Today, 10: 197-204(2005).

In yet another aspect, the compounds and compositions described hereinmay be used for treating a cancer caused by the proliferation ofneoplastic cells. Such cancers include e.g., solid tumors, neoplasms,carcinomas, sarcomas, leukemias, lymphomas and the like. In one aspect,cancers that may be treated by the compounds and compositions describedherein include, but are not limited to: cardiac cancer, lung cancer,gastrointestinal cancer, genitourinary tract cancer, liver cancer,nervous system cancer, gynecological cancer, hematologic cancer, skincancer, and adrenal gland cancer. In one aspect, the compounds andcompositions described herein are useful in treating cardiac cancersselected from sarcoma (angiosarcoma, fibrosarcoma, rhabdomyosarcoma,liposarcoma), myxoma, rhabdomyoma, fibroma, lipoma and teratoma. Inanother aspect, the compounds and compositions described herein areuseful in treating a lung cancer selected from bronchogenic carcinoma(squamous cell, undifferentiated small cell, undifferentiated largecell, adenocarcinoma), alveolar (bronchiolar) carcinoma, bronchialadenoma, sarcoma, lymphoma, chondromatous hamartoma, and mesothelioma.In one aspect, the compounds and compositions described herein areuseful in treating a gastrointestinal cancer selected from esophagus(squamous cell carcinoma, adenocarcinoma, leiomyosarcoma, lymphoma),stomach (carcinoma, lymphoma, leiomyosarcoma), pancreas (ductaladenocarcinoma, insulinoma, glucagonoma, gastrinoma, carcinoid tumors,vipoma), small bowel (adenocarcinoma, lymphoma, carcinoid tumors,Kaposi's sarcoma, leiomyoma, hemangioma, lipoma, neurofibroma, fibroma),and large bowel (adenocarcinoma, tubular adenoma, villous adenoma,hamartoma, leiomyoma). In one aspect, the compounds and compositionsdescribed herein are useful in treating a genitourinary tract cancerselected from kidney (adenocarcinoma, Wilm's tumor [nephroblastoma],lymphoma, leukemia), bladder and urethra (squamous cell carcinoma,transitional cell carcinoma, adenocarcinoma), prostate (adenocarcinoma,sarcoma), and testis (seminoma, teratoma, embryonal carcinoma,teratocarcinoma, choriocarcinoma, sarcoma, interstitial cell carcinoma,fibroma, fibroadenoma, adenomatoid tumors, lipoma). In one aspect, thecompounds and compositions described herein are useful in treating aliver cancer selected from hepatoma (hepatocellular carcinoma),cholangiocarcinoma, hepatoblastoma, angio sarcoma, hepatocellularadenoma, and hemangioma.

In some embodiments, the compounds described herein relate to treating,a bone cancer selected from osteogenic sarcoma (osteosarcoma),fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma, Ewing'ssarcoma, malignant lymphoma (reticulum cell sarcoma), multiple myeloma,malignant giant cell tumor chordoma, osteochondroma (osteocartilaginousexostoses), benign chondroma, chondroblastoma, chondromyxofibroma,osteoid osteoma and giant cell tumors.

In one aspect, the compounds and compositions described herein areuseful in treating a nervous system cancer selected from skull (osteoma,hemangioma, granuloma, xanthoma, osteitis deformans), meninges(meningioma, meningiosarcoma, gliomatosis), brain (astrocytoma,medulloblastoma, glioma, ependymoma, germinoma [pinealoma], glioblastomamultiform, oligodendroglioma, schwannoma, retinoblastoma, congenitaltumors), and spinal cord (neurofibroma, meningioma, glioma, sarcoma).

In one aspect, the compounds and compositions described herein areuseful in treating a gynecological cancer selected from uterus(endometrial carcinoma), cervix (cervical carcinoma, pre-tumor cervicaldysplasia), ovaries (ovarian carcinoma [serous cystadenocarcinoma,mucinous cystadenocarcinoma, unclassified carcinoma], granulosa-thecalcell tumors, Sertoli-Leydig cell tumors, dysgerminoma, malignantteratoma), vulva (squamous cell carcinoma, intraepithelial carcinoma,adenocarcinoma, fibrosarcoma, melanoma), vagina (clear cell carcinoma,squamous cell carcinoma, botryoid sarcoma (embryonal rhabdomyosarcoma),and fallopian tubes (carcinoma).

In one aspect, the compounds and compositions described herein areuseful in treating a skin cancer selected from malignant melanoma, basalcell carcinoma, squamous cell carcinoma, Karposi's sarcoma, molesdysplastic nevi, lipoma, angioma, dermatofibroma, keloids, andpsoriasis.

In one aspect, the compounds and compositions described herein areuseful in treating an adrenal gland cancer selected from neuroblastoma.

In one aspect, the compounds and compositions described herein areuseful in treating cancers that include, but are not limited to:leukemias including acute leukemias and chronic leukemias such as acutelymphocytic leukemia (ALL), Acute myeloid leukemia (AML), chroniclymphocytic leukemia (CLL), chronic myelogenous leukemia (CML) and HairyCell Leukemia; lymphomas such as cutaneous T-cell lymphomas (CTCL),noncutaneous peripheral T-cell lymphomas, lymphomas associated withhuman T-cell lymphotrophic virus (HTLV) such as adult T-cellleukemia/lymphoma (ATLL), Hodgkin's disease and non-Hodgkin's lymphomas,large-cell lymphomas, diffuse large B-cell lymphoma (DLBCL); Burkitt'slymphoma; mesothelioma, primary central nervous system (CNS) lymphoma;multiple myeloma; childhood solid tumors such as brain tumors,neuroblastoma, retinoblastoma, Wilm's tumor, bone tumors, andsoft-tissue sarcomas, common solid tumors of adults such as head andneck cancers (e.g., oral, laryngeal and esophageal), genito urinarycancers (e.g., prostate, bladder, renal, uterine, ovarian, testicular,rectal and colon), lung cancer, breast cancer, pancreatic cancer,melanoma and other skin cancers, stomach cancer, brain tumors, livercancer and thyroid cancer.

In one aspect, the present disclosure provides a method of treating acondition described herein comprising administering to a subject aneffective amount of a compound, or pharmaceutically acceptable saltdescribed herein, or a composition thereof.

Also provided is one or more of the compounds, or pharmaceuticallyacceptable salts thereof described herein, or a provided composition,for treating a condition described herein.

Also provided is the use of one or more of the compounds, orpharmaceutically acceptable salts thereof described herein for themanufacture of a medicament for treating a condition described herein.

Subjects may also be selected to be suffering from one or more of thedescribed conditions before treatment with one or more of the describedcompounds, or pharmaceutically acceptable salts or compositionscommences.

The present disclosure also provides pharmaceutically acceptablecompositions comprising a compound described herein, or apharmaceutically acceptable salt thereof; and a pharmaceuticallyacceptable carrier. These compositions can be used to treat one or moreof the conditions described above.

Compositions described herein may be administered orally, parenterally,by inhalation spray, topically, rectally, nasally, buccally, vaginallyor via an implanted reservoir. The term “parenteral” as used hereinincludes subcutaneous, intravenous, intramuscular, intra-articular,intra-synovial, intrasternal, intrathecal, intrahepatic, intralesionaland intracranial injection or infusion techniques. Liquid dosage forms,injectable preparations, solid dispersion forms, and dosage forms fortopical or transdermal administration of a compound are included herein.

It should also be understood that a specific dosage and treatmentregimen for any particular patient will depend upon a variety offactors, including age, body weight, general health, sex, diet, time ofadministration, rate of excretion, drug combination, the judgment of thetreating physician, and the severity of the particular disease beingtreated. The amount of a provided compound in the composition will alsodepend upon the particular compound in the composition.

EXEMPLIFICATION General Information

Spots were visualized by UV light (254 and 365 nm). Purification bycolumn and flash chromatography was carried out using silica gel(200-300 mesh). Solvent systems are reported as the ratio of solvents.

¹H NMR spectra were recorded on Bruker Avance III 400 MHz or a BrukerFourier 300 MHz. ¹H chemical shifts are reported in δ values in ppm withtetramethylsilane (TMS, =0.00 ppm) as the internal standard. See, e.g.,the data provided in Table 1.

LCMS spectra were obtained on an Agilent 1200 series 6110 or 6120 massspectrometer with ESI (+) ionization mode. (Column: C18 (50×4.6 mm, 5μm) operating in ES (+) or (−) ionization mode; T=30° C.; flow rate=1.5mL/min; detected wavelength: 220 nm. See, e.g., the data provided inTable 1.

Example 1. Synthesis of Compound 1

Synthesis of Intermediate 101. To a solution of Intermediate 100 (350 g,3.00 mol) in DMF (5500 mL) at 0° C. was added NaH (360 g, 9.00 mol), andthe mixture was stirred for 30 min at this temperature. A solution ofpropargyl bromide (1.43 kg, 12.0 mol) in DMF (1500 mL) was added, andthe reaction mixture was warmed to room temperature and stirred for 4 h.The reaction mixture was then quenched with saturated ammonium chloridesolution and extracted with EtOAc (2000 mL×3). The combined organiclayers were washed with saturated aqueous NaCl (2000 mL×2), dried overNa₂SO₄, filtered, and concentrated in vacuo. The crude product waspurified by column chromatography using silica gel to affordIntermediate 101 (245 g, 42.5%) as a yellow oil. ¹H NMR (CDCl₃, 400MHz): δ (ppm) 1.48 (s, 9H), 2.22 (t, 2H, J=4.8 Hz), 4.17 (s, 4H).

Synthesis of Intermediate 102. To a solution of Intermediate 101 (270 g,1.40 mol) and Cp*RuCl(cod) (13.5 g, 35.6 mmol) in dry, degassed1,2-dichloroethane (2200 mL) was added a solution of chloroacetonitrile(157 g, 2.10 mol) in dry, degassed 1,2-dichloroethane (500 mL) over 15min under an Ar atmosphere at room temperature. The reaction mixture wasthen warmed to 60° C. and stirred for 0.5 h, whereupon the solvent wasevaporated and the crude residue was purified by column chromatographyusing silica gel to give Intermediate 102 (210 g, 56.0%) as an off-whitesolid. ¹H NMR (CDCl₃, 400 MHz): δ (ppm) 1.52 (s, 9H), 4.67-4.73 (m, 6H),7.40 (d, 1H, J=19.2 Hz), 8.50 (d, 1H, J=15.6 Hz). MS 269.1 [M+H]⁺.

Synthesis of Intermediate 103. A solution of Intermediate 102 (210 g,784 mmol) in MeOH (4000 mL) was treated with Pd/C (21.0 g), and thereaction mixture was stirred at room temperature under an H₂ atmospherefor 2 h. The reaction mixture was then filtered, and the filtrate wasconcentrated in vacuo to provide Intermediate 103 (120 g, 65.6%) as anoff-white solid. ¹H NMR (CDCl₃, 400 MHz): δ (ppm) 1.53 (s, 9H), 2.98 (s,3H), 4.86-4.90 (m, 4H), 7.53-7.60 (m, 1H), 8.62-8.67 (m, 1H). MS 235.1[M+H]⁺.

Synthesis of Intermediate 104. A solution of 4N HCl (600 mL, HCl inEtOAc) was added dropwise to a 0° C. solution of Intermediate 103 (120g, 513 mmol) in EtOAc (600 mL). The reaction mixture was then warmed toroom temperature and stirred for 1 h. The solvent was removed byfiltration to give Intermediate 104 as a white solid. ¹H NMR (DMSO_d₆,400 MHz): δ (ppm) 2.75 (s, 3H), 4.73-4.80 (m, 4H), 7.97 (s, 1H), 8.20(s, 1H). MS 135.1 [M+H]⁺.

Synthesis of Intermediate 105. A mixture of Intermediate 104 (513 mmol),Intermediate A3 (151 g, 308 mmol) and Na₂CO₃ (272 g, 2.57 mol) in DMSOwas stirred at room temperature for 3 h. After the reaction had reachedcompletion according to LCMS, the reaction mixture was poured into coldwater, extracted with EtOAc, and the layers were separated. The organiclayer was then concentrated in vacuo, and the residue was trituratedwith EtOAc, and then filtered to provide Intermediate 105 (80.0 g, 38%from compound 5) as a yellow solid. ¹H NMR (DMSO_d₆, 400 MHz): δ (ppm)2.49 (s, 3H), 4.70-4.96 (m, 4H), 7.29-7.35 (m, 2H), 7.45-7.49 (m, 1H),7.50-7.51 (m, 1H), 8.08-8.14 (m, 1H), 8.46 (d, 2H, J=8.4 Hz), 10.11(brs, 1H). MS 412.1 [M+H]⁺.

Synthesis of Compound 1. A mixture of Intermediate 105 (80.0 g, 195mmol) and Pd/C (8.00 g) in MeOH (2500 mL) was stirred at roomtemperature for 1 h under a H₂ atmosphere. After 1 h, Pd/C was removedby filtration through Celite. The filtrate was concentrated and theresidue was purified by silica gel column chromatography to provideCompound 1 (52.0 g, 70.3%) as a gray solid. ¹H NMR (DMSO_d₆, 400 MHz): δ(ppm) 2.48 (s, 3H), 4.77 (s, 4H), 5.28 (s, 2H), 7.16-7.18 (m, 2H),7.28-7.31 (m, 2H), 7.40-7.42 (m, 1H), 7.92-7.94 (m, 1H), 8.45 (s, 1H),8.56 (s, 1H). MS 382.1 [M+H]⁺.

Synthesis of Intermediate A2. A mixture of Intermediate A1 (300 g, 1.73mol), 4-fluorophenylboronic acid (265 g, 1.91 mmol) and Cs₂CO₃ (1.13 kg,3.46 mol) in dioxane/H₂O (6000 mL/600 mL) was treated with Pd(PPh₃)₄(72.6 g, 86.3 mmol) under a N₂ atmosphere. The mixture was stirred at95° C. for 2 h and then was concentrated in vacuo. The residue was takenup in EtOAc (4000 mL) and the resulting solution was washed with brine(1000 mL×3). The combined organic layers were dried over anhydrousNa₂SO₄, filtered, and then concentrated in vacuo. The crude residue waspurified by column chromatography on silica gel to provide IntermediateA2 (240 g, crude) as a yellow solid. ¹H NMR (CDCl₃, 400 MHz): δ (ppm)6.90-6.96 (m, 1H), 6.99-7.04 (m, 1H), 7.23-7.26 (m, 1H), 8.02-8.08 (m,1H), 8.47 (d, 1H, J=8.4 Hz). MS 252.0 [M+H]⁺.

Synthesis of Intermediate A3. Phenyl carbonochloridate (354 g, 2.27 mol)was added dropwise to a stirring solution of Intermediate A2 (240 g,crude) in pyridine (4800 mL) at room temperature. After the addition wascompleted, the reaction mixture was heated to 50° C. and stirredovernight. The mixture was then concentrated in vacuo, and the cruderesidue was purified by recrystallization with MTBE to provideIntermediate A3 (240 g, 28.2% from compound A1) as a yellow solid. ¹HNMR (CDCl₃, 400 MHz): δ (ppm) 6.97-7.02 (m, 1H), 7.08-7.39 (m, 11H),8.13 (d, 1H, J=8.4 Hz), 8.24-8.30 (m, 1H), 8.67 (d, 1H, J=8.8 Hz). MS492.1 [M+H]⁺.

Example 2. Synthesis of Compound 2

Synthesis of 107. A mixture of2-chloro-6,7-dihydro-5H-pyrrolo[3,4-b]pyridine hydrochloride (11 g, 57.9mmol), TEA (17.5 g, 173.7 mmol) and (Boc)₂O (13.9 g, 63.7 mmol) in THF(250 mL) was stirred at room temperature for 3 h. The reaction mixturewas then poured into DCM (500 mL), washed with brine (100 mL×3), driedover anhydrous Na₂SO₄ and then concentrated in vacuo. The residue waspurified by column chromatography on silica gel (DCM:EtOAc=100:1˜10:1)to give 107 (13.5 g, 92%) as a white solid. MS 255.2 [M+H]⁺.

Synthesis of 108. A mixture of 107 (13.5 g, 53.1 mmol), potassiumacetate (10.4 g, 106.2 mmol), dppf (883 mg, 1.59 mmol) and palladiumacetate (677 mg, 2.66 mmol) in ethanol (20 mL) was stirred at 100° C.for 16 h under a CO atmosphere at 1.5 MPa. The reaction mixture was thencooled to room temperature and filtered through Celite. The filtrate wasconcentrated in vacuo and the residue was dissolved in DCM (500 mL),washed with brine (10 mL×3), dried over anhydrous Na₂SO₄ and thenconcentrated in vacuo. The residue was purified by column chromatographyon silica gel (PE:EtOAc=8:1˜3:1) to give 108 (13.4 g, 86%) as a whitesolid. MS 292.1 [M+H]⁺.

Synthesis of 109. A mixture of 108 (13.4 g, 45.9 mmol) and NaBH₄ (10.4g, 275.3 mmol) in ethanol (260 mL) was stirred at room temperature for16 h. The reaction mixture was concentrated in vacuo and and the residuewas dissolved with DCM (500 mL), washed with brine (100 mL×3), driedover anhydrous Na₂SO₄ and then concentrated in vacuo. The residue waspurified by column chromatography on silica gel (DCM:MeOH=100:1˜20:1) togive 109 (8.6 g, 75%) as a white solid. MS 251.4 [M+H]⁺.

Synthesis of 110. To a mixture of 109 (8.6 g, 34.4 mmol) in DMF (200 mL)at room temperature was added NaH (60% in mineral oil) (4.1 g, 103.2mmol). The resulting mixture was stirred at room temperature for 30 min,whereupon MeI (14.6 g, 103.2 mmol) was added dropwise. The resultingreaction mixture was stirred at room temperature for 1 h, and thesolution was then diluted with water (300 mL), and extracted with EtOAc(200 mL×3). The combined organic layer was washed with brine (100 mL×3),dried over anhydrous Na₂SO₄ and then concentrated in vacuo. The residuewas purified by column chromatography on silica gel (PE:EtOAc=8:1˜3:1)to give 110 (8.0 g, 88%) as an off-white solid. MS 265.3 [M+H]⁺.

Synthesis of 111. To a solution of 110 (7.6 g, 28.8 mmol) in DCM (70 mL)in an ice bath was added TFA (38 mL) dropwise. The resulting solutionwas stirred at room temperature for 1 h, whereupon the solvent wasremoved in vacuo to give 111 as a crude product. MS 165.2 [M+H]⁺.

Synthesis of 112. A mixture of 111 (28.8 mmol, crude product from laststep), A3 (11.8 g, 24 mmol) and Na₂CO₃ (25.4 g, 240 mmol) in DMSO (200mL) was stirred at room temperature for 16 h. When the reaction hadreached completion, as indicated by LCMS, the solution was diluted withwater (300 mL), and then extracted with EtOAc (200 mL×3). The combinedorganic layers were washed with brine (100 mL×3), dried over anhydrousNa₂SO₄ and then concentrated in vacuo. The residue was purified bycolumn chromatography on silica gel (PE:EtOAc=1:1 to EtOAc) to give 112(7.0 g, 66%) as a yellow solid. MS 442.2 [M+H]⁺.

Synthesis of Compound 2. A mixture of 112 (7.0 g, 15.9 mmol) and Pd/C(2.3 g) in DCM/MeOH (140 mL/140 mL) was stirred at room temperature for2 h under a H₂ atmosphere. Pd/C was then removed by filtration throughthe Celite. The filtrate was concentrated and the residue wasrecrystallized with MTBE to give Compound 2 (4.5 g, 69%) as a lightyellow solid. MS 412.1 [M+H]⁺.

Example 3. Synthesis of Compound 3

Synthesis of Compound 3. Compound 3 was synthesized in a similar mannerto 1, to provide 3 (28 mg, 22%) as an off-white solid. MS 388 [M+H]⁺.

Example 4. Synthesis of Compound 4

Synthesis of 114. To a solution of prop-2-yn-1-amine (5.0 g, 90.9 mmol)and Et₃N (18.4 g, 181.8 mmol) in DCM (100 mL) cooled with an ice bathwas added (Boc)₂O (23.8 g, 109.1 mmol) dropwise. Upon completion ofaddition of (Boc)₂O, the resulting mixture was allowed to warm to roomtemperature, and was stirred at room temperature for 16 h. When thereaction was complete, the mixture was diluted with DCM (200 mL), andthen washed with brine (100 mL×3). The organic layer was dried overNa₂SO₄ and then concentrated in vacuo. The residue was purified bycolumn chromatography on silica gel (PE:EtOAc=100:1˜10:1) to give 114(10 g, 71%) as a colorless oil. MS 178.3 [M+23]⁺, 100.3 [M−56]⁺.

Synthesis of 101. To a solution of 114 (10 g, 64.5 mmol) in DMF (200 mL)was added NaH (60% in mineral oil) (2.84 g, 71 mmol) slowly while thereaction mixture was cooled with an ice bath. The resulting reactionmixture was stirred at room temperature for 1 h, and then3-bromoprop-1-yne (9.2 g, 77.4 mmol) was added into the above mixtureand stirred at room temperature for 2 h. The reaction was then quenchedwith water (500 mL) and extracted with t-BuOMe (250 mL×3). The combinedorganic layer was washed with brine (200 mL×3), dried over anhydrousNa₂SO₄ and then concentrated in vacuo. The residue was purified bycolumn chromatography on silica gel (PE:EtOAc=100:1˜10:1) to give 101(12 g, 96%) as a yellow oil. MS 138.1 [M−56]⁺.

Synthesis of 102. To a solution of 2-chloroacetonitrile (3.13 g, 41.4mmol) and [Cp*RuCl(cod)] (394 mg, 1.0 mmol) in DCE (40 mL) was added asolution of 101 (4.0 g, 20.7 mmol) in DCE (80 mL) dropwise over 30 minunder N₂ atmosphere. The resulting reaction mixture was stirred at 40°C. for 16 h. The solvent was then removed in vacuo, and the cruderesidue was purified by column chromatography on silica gel(PE:EtOAc=10:1˜2:1) to give 102 (2.1 g, 22%) as a tan solid. MS 269.3[M+H]⁺.

Synthesis of 115. A mixture of 102 (1.50 g, 5.6 mmol), 3-fluoroazetidinehydrochloride (932 mg, 8.4 mmol) and K₂CO₃ (2.32 g, 16.8 mmol) in DMF(30 mL) was stirred at 50° C. for 3 h. The mixture was then diluted withwater (60 mL) and extracted with EtOAc (30 mL×4). The combined organiclayers were washed with brine (30 mL×3), dried over anhydrous Na₂SO₄ andthen concentrated in vacuo. The residue was purified by columnchromatography on silica gel (DCM:MeOH=100:1˜30:1) to give 115 (1.4 g,81%) as a white solid. MS 308.2 [M+H]⁺.

Synthesis of 116. To a solution of 115 (200 mg, 0.65 mmol) in DCM (4 mL)was added TFA (2 mL), and the resulting reaction mixture was stirred atroom temperature for 1 h. When LCMS indicated that the reaction wasfinished, the solvent was removed in vacuo to give 116 as a crudeproduct which was used without further purification in the next step. MS208.2 [M+H]⁺.

Synthesis of 117. A mixture of A3 (265 mg, 0.54 mmol) and 116 (0.65mmol, crude product from last step) in DMSO (40 mL) was stirred at roomtemperature for 10 min, and then Na₂CO₃ (458 mg, 4.32 mmol) was added.The resulting reaction mixture was stirred at room temperature for 2 h,then was diluted with water (80 mL), and extracted with EtOAc (40 mL×4).The combined organic layers were washed with brine (40 mL×3), dried overanhydrous Na₂SO₄ and then concentrated in vacuo. The residue waspurified by column chromatography on silica gel (DCM:MeOH=100:1˜50:1) togive 117 (200 mg, 76%) as a yellow solid. MS 485.2 [M+H]⁺.

Synthesis of Compound 4. A mixture of 117 (200 mg, 0.41 mmol) and Pd/C(200 mg) in MeOH (8 mL) was stirred at room temperature for 1 h under H₂atmosphere. The Pd/C was removed by filtration through the Celite, andthe filtrate was concentrated to provide a crude residue, which waspurified by Prep-TLC (DCM:MeOH=10:1) three times to give Compound 4 (26mg, 14%) as a yellow solid.

Example 5. Synthesis of Compound 5

Synthesis of A2. A mixture of 6-chloro-3-nitropyridin-2-amine (4.58 g,26.4 mmol), 2,4-difluorophenylboronic acid (5.00 g, 31.7 mmol) andCs₂CO₃ (25.73 g, 79.2 mmol) in dioxane/H₂O (100 mL/10 mL) was treatedwith Pd(PPh₃)₄(1.10 g, 0.95 mmol) under a N₂ atmosphere. The mixture wasstirred at 100° C. for 2 h and then concentrated in vacuo. The residuewas dissolved in EtOAc (200 mL), and the solution was washed with brine(100 mL×3). The organic layer was dried over anhydrous Na₂SO₄ and thenconcentrated in vacuo. The residue was purified by column chromatographyon silica gel (PE:EtOAc=7:1˜5:1) to give A2 (4.0 g, 61%) as a yellowsolid. MS 252.1 [M+H]⁺.

Synthesis of A3. A stirring solution of A2 (4.0 g, 15.94 mmol) inpyridine (60 mL) was treated with phenyl carbonochloridate (7.50 g,47.81 mmol) dropwise at 0° C. After the addition was completed, thereaction mixture was stirred at 50° C. for 4 h. The mixture was thenconcentrated in vacuo, and the crude residue was purified by columnchromatography on silica gel (PE:DCM=3:2˜1:1) to give A3 (7.1 g, 91%) asa yellow solid. MS 492.1 [M+H]⁺.

Synthesis of 118. A solution of tert-butyl3-oxopyrrolidine-1-carboxylate (15.0 g, 81.1 mmol) and DMF-DMA (29.0 g,243.3 mmol) in THF (150 mL) was stirred at 70° C. for 16 h. The solutionwas concentrated in vacuo to give 118 as a crude product which was useddirectly in the next step. MS 241.1 [M+H]⁺.

Synthesis of 119. To a solution of 118 (81.1 mmol, crude product fromlast step) in EtOH (100 mL) was added Et₃N (40.4 g, 0.4 mol) andacetimidamide hydrochloride (30.1 g, 0.32 mol). The resulting solutionwas stirred at 80° C. for 24 h. After the solvent was removed in vacuo,the residue was diluted with water (100 mL) and extracted with DCM (50mL×3). The combined organic layers were washed with brine (50 mL×3),dried over anhydrous Na₂SO₄ and then concentrated in vacuo. The residuewas purified by column chromatography on silica gel (PE:DCM=10:1˜1:2) togive 119 (10.5 g, 55%) as a brown solid. MS 236.2 [M+H]⁺.

Synthesis of 120. A solution of 119 (600 mg, 2.55 mmol) in dioxane/HCl(4 N, 10 mL) was stirred at room temperature for 1 h. The solution wasconcentrated in vacuo to give 120 (340 mg, 77%) as a white solid whichwas used without further purification. MS 136.2 [M+H]⁺.

Synthesis of 121. A mixture of A3 (231 mg, 0.47 mmol) and 120 (160 mg,0.94 mmol) in DMSO (5 mL) was stirred at room temperature for 10 min.Then Na₂CO₃ (399 mg, 3.76 mmol) was added into above mixture and theresulting mixture was stirred at room temperature for 2 h. After thereaction had gone to completion, as indicated by LCMS, the reactionmixture was diluted with water (30 mL) and extracted with EtOAc (10mL×3). The combined organic layers were washed with brine (10 mL×3),dried over anhydrous Na₂SO₄ and then concentrated in vacuo. The cruderesidue was purified by column chromatography on silica gel(DCM:MeOH=100:1˜50:1) to provide 121 (120 mg, 62%) as a yellow solid. MS413.2 [M+H]⁺.

Synthesis of Compound 5. A mixture of 121 (120 mg, 0.29 mmol) and Pd/C(120 mg) in MeOH (5 mL) was stirred at room temperature for 30 min undera H₂ atmosphere. The Pd/C was then removed by filtration through theCelite, the filtrate was concentrated, and the resulting crude residuewas purified by Prep-TLC (DCM:MeOH=10:1) to give Compound 5 (52 mg, 47%)as a white solid. MS 383.2 [M+H]⁺, 405.0 [M+Na]⁺.

Example 6. Synthesis of Compound 6

Synthesis of A4. A stirred solution of 6-bromo-3-nitropyridin-2-amine(5.0 g, 23.0 mmol) and Et₃N (6.9 g, 69.0 mmol) in THF (60 mL) wastreated with phenyl carbonochloridate (10.8 g, 69.0 mmol) dropwise at 0°C. After the addition was completed, the mixture was stirred at roomtemperature for 1 h. The reaction mixture was then filtered andconcentrated in vacuo. The resulting crude residue was recrystallizedfrom petroleum ether to give A4 (10.2 g, 97%) as a light yellow solid.MS 458.0, 460.0 [M+H]⁺.

Synthesis of 122 and 122-A. To a solution of tert-butyl4,6-dihydropyrrolo[3,4-c]pyrazole-5(2H)-carboxylate (15.0 g, 71.8 mmol)in DMF (150 mL) was added NaH (60% in mineral oil) (8.6 g, 215.4 mmol)while the reaction mixture was cooled with an ice bath. When theaddition was complete, the resulting mixture was allowed to warm to roomtemperature and was stirred at room temperature for 30 min. At thispoint, 1-bromo-2-methoxyethane (19.8 g, 143.6 mmol) was added into thereaction mixture, and stirring was continued at room temperature for 2h. The reaction mixture was then quenched with water (300 mL), andextracted with EtOAc (150 mL×3). The combined organic layer was washedwith brine (100 mL×3), dried over anhydrous Na₂SO₄ and then concentratedin vacuo. The residue was purified by column chromatography on silicagel (DCM:MeOH=100:1˜30:1) to give a mixture of 122 and 122-A (19.0 g,99%) as a colorless oil. MS 268.2 [M+H]⁺.

Synthesis of 123 and 123-A. To a solution of 122 and 122-A (6.5 g, 24.3mmol) in DCM (60 mL) cooled with an ice bath was added TFA (30 mL). Thereaction mixture was stirred at room temperature for 1 h, whereupon thesolvent was removed in vacuo to give 123 and 123-A as a crude productmixture which was used directly in the next step without furtherpurification. MS 168.1 [M+H]⁺.

Synthesis of 124 and 124-A. To a solution of 123 and 123-A (24.3 mmol,crude product from last step) and A4 (9.3 g, 20.3 mmol) in DMSO (200 mL)was added Na₂CO₃ (21.5 g, 203 mmol), and the reaction mixture wasstirred at room temperature for 4 h. The mixture was then diluted withwater (400 mL) and extracted with EtOAc (200 mL×3). The combined organiclayers were washed with brine (100 mL×3), dried over anhydrous Na₂SO₄and then concentrated in vacuo. The residue was purified by columnchromatography on silica gel (DCM:MeOH=100:1˜30:1) to give a mixture of124 and 124-A (4.5 g, 50%) as a yellow solid. MS 411.0, 413.1 [M+H]⁺.

Synthesis of 125 and 125-A. A mixture of 124 and 124-A (500 mg, 1.22mmol), 5-chlorothiophen-2-ylboronic acid (237 mg, 1.46 mmol) and K₂CO₃(169 mg, 1.23 mmol) in dioxane/H₂O (10 mL/2 mL) was treated withPd(PPh₃)₄ (45 mg, 0.06 mmol) under a N₂ atmosphere. The reaction mixturewas stirred at 50° C. for 3 h and then concentrated in vacuo. Theresidue was taken up in EtOAc (30 mL), and the resulting solution waswashed with brine (10 mL×3). The organic layer was then dried overanhydrous Na₂SO₄ and concentrated in vacuo. The crude residue waspurified by Prep-TLC (DCM:MeOH=20:1) to give a mixture of 125 and 125-A(450 mg, 82%) as a yellow solid. MS 449.2 [M+H]⁺.

Synthesis of Compound 6 and Compound 6A. A mixture of 125 and 125-A (450mg, 1.0 mmol) and Raney Ni (100 mg) in DCM/MeOH (6 mL/6 mL) was stirredat room temperature for 1 h under a H₂ atmosphere. Raney Ni was thenremoved by filtration through Celite, the filtrate was concentrated envacuo, and the residue was purified by Prep-TLC (DCM:MeOH=10:1). Themixture of regioisomers was then separated by using chiral HPLC(Column:Chiralcel OD-3; Solvent:MeOH; Flow rate: 2 mL/min; RT₁₈₄₃=3.477min, RT_(1843A)=4.142 min) to give Compound 6 (99 mg, 24%) as a whitesolid (MS 419.2 [M+H]⁺) and Compound 6A (50 mg, 12%) as a white solid.MS 419.2 [M+H]⁺.

Example 7. Synthesis of Compound 7

Synthesis of 118. A solution of tert-butyl3-oxopyrrolidine-1-carboxylate (600 mg, 3.24 mmol) and DMF-DMA (1.2 g,9.72 mmol) in THF (10 mL) was stirred at 70° C. for 16 h. The solutionwas concentrated in vacuo to give 118 as a crude product which was useddirectly in the next step. MS 241.1 [M+H]⁺.

Synthesis of 126. To a solution of 118 (3.24 mmol, crude product fromlast step) in EtOH (10 mL) was added Et₃N (1.6 g, 16.2 mol) andpropionimidamide hydrochloride (1.4 g, 13.0 mmol). The resultingsolution was stirred at 80° C. for 20 h, whereupon the solvent wasremoved in vacuo, the residue was diluted with water (10 mL), and themixture was then extracted with DCM (10 mL×3). The combined organiclayers were washed with brine (10 mL×3), dried over anhydrous Na₂SO₄ andthen concentrated in vacuo. The residue was purified by columnchromatography on silica gel (PE:DCM=10:1˜1:2) to give 126 (450 mg, 56%)as a brown solid. MS 250.2 [M+H]⁺.

Synthesis of 127. A solution of 126 (300 mg, 1.2 mmol) in DCM (6 mL) wastreated with TFA (3 mL), and the reaction mixture was stirred at roomtemperature for 1 h. After 1 h, the reaction was complete, as indicatedby LCMS, and the reaction mixture was concentrated in vacuo to give 127as a crude product which was used directly in the next step withoutfurther purification. MS 150.2 [M+H]⁺.

Synthesis of 128. A mixture of A3 (294 mg, 0.6 mmol) and 127 (1.2 mmol,crude product from last step) in DMSO (10 mL) was stirred at roomtemperature for 10 min. Then Na₂CO₃ (636 mg, 6.0 mmol) was added, andthe resulting mixture was stirred at room temperature for 2 h. After thereaction was complete, as indicated by LCMS, the reaction mixture wasdiluted with water (30 mL) and extracted with EtOAc (10 mL×3). Thecombined organic layers were washed with brine (10 mL×3), dried overanhydrous Na₂SO₄ and then concentrated in vacuo. The residue waspurified by column chromatography on silica gel (DCM:MeOH=100:1˜50:1) toprovide 128 (136 mg, 53%) as a yellow solid. MS 427.2 [M+H]⁺.

Synthesis of Compound 7. A mixture of 128 (120 mg, 0.28 mmol) and RaneyNi (120 mg) in MeOH (5 mL) was stirred at room temperature for 1 h undera H₂ atmosphere. The Raney Ni was then removed by filtration throughCelite, the filtrate was concentrated, and the crude residue waspurified by Prep-TLC (DCM:MeOH=10:1) to give Compound 7 (80 mg, 72%) asa yellow solid. MS 397.1 [M+H]⁺.

Example 8. Synthesis of Compound 8

Synthesis of 129 and 129-A. A mixture of 124 and 124-A (350 mg, 0.85mmol), 2-fluorophenylboronic acid (143 mg, 1.02 mmol) and K₂CO₃ (352 mg,2.55 mmol) in dioxane/H₂O (10 mL/2 mL) was treated with Pd(PPh₃)₄ (49mg, 0.04 mmol) under a N₂ atmosphere. The reaction mixture was stirredat 90° C. for 3 h and then concentrated in vacuo. The crude residue wastaken up in EtOAc (30 mL), and the resulting solution was washed withbrine (10 mL×3). The organic layer was dried over anhydrous Na₂SO₄ andthen concentrated in vacuo. The residue was purified by Prep-TLC(PE:EA=5:1) to give a mixture of 129 and 129-A (300 mg, 83%) as a yellowsolid. MS 427.2 [M+H]⁺.

Synthesis of Compound 8 and Compound 8A. A mixture of 129 and 129-A (300mg, 0.70 mmol) and Pd/C (80 mg) in DCM/MeOH (5 mL/5 mL) was stirred atroom temperature for 1 h under a H₂ atmosphere. The Pd/C was thenremoved by filtration through Celite, the filtrate was concentrated, andthe crude residue was purified by Prep-TLC (DCM:MeOH=10:1). The mixtureof regioisomers was then separated using chiral HPLC (Column:ChiralcelOJ-3; Solvent:MeOH; Flow rate: 2 mL/min; RT₁₈₄₉=1.201 min,RT_(1849A)=2.244 min) to give 8 (105 mg, 37%) as a yellow solid (MS397.2 [M+H]⁺) and 8A (98 mg, 35%) as a yellow solid. MS 397.2 [M+H]⁺.

Example 9. Synthesis of Compound 9

Synthesis of 130. A mixture of 6-chloro-3-nitropyridin-2-amine (0.5 g,2.9 mmol), 2-fluorophenylboronic acid (487 mg, 3.48 mmol) and K₂CO₃(1.20 g, 8.7 mmol) in dioxane/H₂O (10 mL/1 mL) was treated withPd(PPh₃)₄(17 mg, 0.01 mmol) under a N₂ atmosphere. The reaction mixturewas stirred at 90° C. for 2 h and then concentrated in vacuo. The cruderesidue was taken up in EtOAc (200 mL), and the resulting solution waswashed with brine (100 mL×3). The organic layer was then dried overanhydrous Na₂SO₄ and concentrated in vacuo. The residue was purified bycolumn chromatography on silica gel (PE:EtOAc=10:1˜3:1) to give 130 (301mg, 45%) as a yellow solid. MS 234.2 [M+H]⁺.

Synthesis of 131. To a stirred solution of 130 (301 mg, 1.3 mmol) inpyridine (10 mL) was added phenyl carbonochloridate (608 mg, 3.9 mmol)dropwise while the reaction mixture was cooled with an ice bath. Theresulting reaction mixture was stirred at 55° C. for 4 h, whereupon thereaction mixture was concentrated in vacuo. The resulting crude residuewas purified by column chromatography on silica gel (PE:EtOAc=8:1˜3:1)to give 131 (500 mg, 82%) as a yellow solid. MS 474.2 [M+H]⁺.

Synthesis of 132. To an ice bath-cooled flask of MeOH (30 mL) wastreated with NaH (60% in mineral oil) (940 mg, 23.5 mmol), and thereaction mixture was stirred at 0° C. for 30 min. Compound 102 (2.1 g,7.8 mmol) was then added, and the reaction mixture was stirred at 35° C.for 16 h. At this point, the reaction mixture was quenched with water(30 mL), extracted with DCM (10 mL×3), and the combined organic layerswere washed with brine (10 mL×3), dried over anhydrous Na₂SO₄ and thenconcentrated in vacuo. The resulting crude residue was purified bycolumn chromatography on silica gel (PE:EtOAc=100:1˜10:1) to give 132(1.8 g, 94%) as a beige colored solid. MS 265.1 [M+H]⁺.

Synthesis of 133. To a solution of 132 (220 mg, 0.83 mmol) in DCM (6 mL)was added TFA (2 mL) dropwise, with the reaction mixture cooled in anice bath. The reaction was stirred at room temperature 1 h, whereuponthe solvent was removed in vacuo to give 133 as a crude product whichwas used directly in the next step. MS 165.1 [M+H]⁺.

Synthesis of 134. A mixture of 131 (313 mg, 0.64 mmol) and 133 (0.83mmol, crude product from last step) in DMSO (10 mL) was treated withNa₂CO₃ (678 mg, 6.4 mmol), and the reaction mixture was then stirred atroom temperature for 2 h. At this point, the reaction mixture wasdiluted with water (20 mL) and extracted with EtOAc (20 mL×3). Thecombined organic layers were washed with brine (20 mL×3), dried overanhydrous Na₂SO₄ and then concentrated in vacuo. The residue waspurified by column chromatography on silica gel (EA to EA:MeOH=50:1) togive 134 (200 mg, 74%) as a yellow solid. MS 424.0 [M+H]⁺.

Synthesis of Compound 9. A mixture of 134 (200 mg, 0.47 mmol) and Pd/C(200 mg) in DCM/MeOH (4 mL/4 mL) was stirred at room temperature for 1 hunder a H₂ atmosphere. The Pd/C was then removed by filtration throughCelite, the filtrate was concentrated and the resulting crude residuewas purified by Prep-TLC (DCM:MeOH=10:1) to give Compound 9 (105 mg,57%) as a yellow solid. MS 394.2 [M+H]⁺.

Example 10. Synthesis of Compound 10

Synthesis of 135 and 135-A. To a solution of tert-butyl4,6-dihydropyrrolo[3,4-c]pyrazole-5(2H)-carboxylate (250 mg, 1.2 mmol)in DMF (5 mL) was added NaH (96 mg, 2.4 mmol (60% in mineral oil)), withthe reaction mixture being cooled with an ice bath. The resultingmixture was stirred at room temperature for 1 h, whereupon iodoethane(374 mg, 2.4 mmol) was added, and the resulting reaction mixture wasstirred at room temperature for 2 h. The reaction mixture was thendiluted with water (10 mL) and extracted with EtOAc (10 mL×3). Thecombined organic layers were washed with brine (10 mL×3), dried overanhydrous Na₂SO₄ and then concentrated in vacuo to give 135 and 135-A asa crude product. MS 238.2 [M+H]⁺.

Synthesis of 136 and 136-A. To a solution of 135 and 135-A (1.2 mmol,crude product from last step) in DCM (6 mL) was added TFA (2 mL)dropwise while the reaction mixture was cooled with an ice bath. Thereaction mixture was stirred at room temperature 1 h, whereupon thesolvent was removed in vacuo to give 136 and 136-A as a crude productwhich was used in the next step without further purification. MS 138.2[M+H]⁺.

Synthesis of 137. A mixture of 136 and 136-A (1.2 mmol, crude productfrom last step) and A3 (491 mg, 1.0 mmol) in DMSO (10 mL) was stirred atroom temperature for 10 min, then Na₂CO₃ (848 mg, 8.0 mol) was added,and the reaction mixture was stirred at room temperature for 2 h. Thereaction mixture was then diluted with water (20 mL) and extracted withEtOAc (20 mL×3). The combined organic layers were washed with brine (20mL×3), dried over anhydrous Na₂SO₄ and then concentrated in vacuo. Thecrude residue was purified by column chromatography on silica gel(DCM:MeOH=100:1˜50:1) to give a crude product which was a mixture of theregioisomers 137 and 137-A. The crude product was further purified byPrep-TLC (DCM:MeOH=30:1) to give 137 (150 mg, 36%) as a yellow solid. MS415.1 [M+H]⁺.

Synthesis of Compound 10. A mixture of 137 (150 mg, 0.36 mmol) and Pd/C(150 mg) in MeOH (5 mL) was stirred at room temperature for 1 h under aH₂ atmosphere. The Pd/C was then removed by filtration through Celite,the filtrate was concentrated and the residue was purified by Prep-TLC(DCM:MeOH=15:1) to give Compound 10 (85 mg, 61%) as a yellow solid. MS385.1 [M+H]⁺.

TABLE 1 Spectrometric Data for Compounds MS MS ¹H NMR Data (400 MHz, No.Structure Calc. found DMSO-d₆) 1

381 382 δ 2.48 (s, 3H), 4.77 (s, 4H), 5.28 (s, 2H), 7.16-7.18 (m, 2H),7.28-7.31 (m, 2H), 7.40-7.42 (m, 1H), 7.92-7.94 (m, 1H), 8.45 (s, 1H),8.56 (s, 1H). 2

411 412 δ 8.59 (s, 1H), 7.98-7.92 (m, 1H), 7.81 (d, J = 7.6 Hz, 1H),7.43-7.40 (m, 1H), 7.36-7.26 (m, 2H), 7.18-7.14 (m, 2H), 5.28 (s, 2H),4.77 (s, 4H), 4.51 (s, 2H), 3.37 (s, 3H). 3

387 388 δ 8.55 (s, 1H), 7.95 (q, J = 8.80 Hz, 1H), 7.42 (d, J = 2.40 Hz,1H), 7.33-7.27 (m, 1H), 7.19- 7.14 (m, 2H), 5.27 (s, 2H), 4.68 (d, J =34.40 Hz, 4H), 2.70 (s, 3H). 4

454 455 δ 8.59 (s, 1H), 8.50 (s, 1H), 7.97- 7.91 (m, 1H), 7.41 (dd, J =8.0, 2.0 Hz, 1H), 7.37 (s, 1H), 7.33- 7.27 (m, 1H), 7.19-7.14 (m, 2H),5.29-5.26 (m, 2.5H), 5.14- 5.12 (m, 0.5H), 4.80 (s, 4H), 3.76 (s, 2H),3.66-3.58 (m, 2H), 3.28-3.24 (m, 1H), 3.22- 3.19 (m, 1H). 5

382 383 δ 8.70 (s, 1H), 8.65 (s, 1H), 7.97- 7.91 (m, 1H), 7.42 (dd, J =8.0, 2.0 Hz, 1H), 7.33-7.27 (m, 1H), 7.18-7.14 (m, 2H), 5.29 (s, 2H),4.77 (d, J = 5.6 Hz, 4H), 2.64 (s, 3H). 6

418 419 δ 8.41 (s, 1H), 7.56 (s, 1H), 7.51 (d, J = 8.4 Hz, 1H), 7.34 (d,J = 4.0 Hz, 1H), 7.12 (d, J = 8.4 Hz, 1H), 7.05 (d, J = 4.0 Hz, 1H),5.24 (s, 2H), 4.50 (s, 4H), 4.26 (t, J = 5.2 Hz, 2H), 3.68 (t, J = 5.6Hz, 2H), 3.24 (s, 3H). 7

396 396 δ 8.73 (s, 1H), 8.64 (s, 2H), 7.97- 7.91 (m, 1H), 7.42 (dd, J =8.0, 3.0 Hz, 1H), 7.32-7.26 (m, 1H), 7.18-7.14 (m, 2H), 5.29 (s, 2H),4.78 (d, J = 10.0 Hz, 4H), 2.92 (q, J = 7.6 Hz, 2H), 1.29 (t, J = 7.6Hz, 3H). 8

396 397 δ 8.47 (s, 1H), 7.93-7.89 (m, 1H), 7.57 (s, 1H), 7.45-7.43 (m,1H), 7.35-7.28 (m, 1H), 7.25-7.22 (m, 2H), 7.17 (d, J = 8.4 Hz, 1H),5.24 (s, 2H), 4.51 (s, 4H), 4.26 (t, J = 5.6 Hz, 2H), 3.68 (t, J = 5.2Hz, 2H), 3.24 (s, 3H). 9

393 394 δ 8.58 (s, 1H), 8.53 (s, 1H), 7.93- 7.89 (m, 1H), 7.46-7.44 (m,2H), 7.35-7.32 (m, 1H), 7.28- 7.22 (m, 2H), 7.17 (d, J = 8.4 Hz, 1H),5.28 (s, 2H), 4.83 (s, 4H), 4.52 (s, 2H), 3.38 (s, 3H). 10

384 385 δ 8.47 (s, 1H), 7.96-7.93 (m, 1H), 7.60 (s, 1H), 7.40 (dd, J =8.0, 2.4 Hz, 1H), 7.32-7.26 (m, 1H), 7.18-7.14 (m, 2H), 5.25 (s, 2H),4.52 (s, 4H), 4.13 (q, J = 7.2 Hz, 2H), 1.38 (t, J = 7.2 Hz, 3H), 3.24(s, 3H).

HDAC2 and HDAC1 Enzymatic Assay (HDAC2 IC50 Data)

The following describes an assay protocol for measuring thedeacetylation of a peptide substrate by the enzymes HDAC2 or HDAC1.Enzyme, substrate, and cofactors are combined in a well of a microtiterplate and incubated for 3 hours at 25° C. At the end of the incubation,the reaction is quenched by the addition of an SDS-containing buffer.Substrate and product are separated and quantified electrophoreticallyusing the microfluidic-based LabChip 3000 Drug Discovery System fromCaliper Life Sciences. The peptide substrate used in this assay isFAM-TSRHK(AC)KL-CONH2 (FAM is carboxyfluorescein). Peptide shouldbe >98% purity by Capillary Electrophoresis.

-   -   1. To a well of a 384-well plate, add 5 μL of 2× enzyme buffer.        Using Labcyte Echo 550, add 100 nl compound. Enzyme and compound        may be pre-incubated at this time if desired.    -   2. Add 5 μL of 2× substrate buffer.    -   3. Incubate plate at 25° C. for 17 hours.    -   4. Terminate reaction by adding 40 μL of 1.55× stop buffer.    -   5. Create job on a Caliper LabChip® 3000 Drug Discovery System.    -   6. Load the plate and start electrophoresis using blue laser        (480 nm) for excitation and green CCD (520 nm) for detection        (CCD2).        Reaction time=17 hours; Reaction temperature=25° C.

Final Assay Reaction Mixture

100 mM HEPES, pH 7.5 0.1% BSA 0.01% Triton X-100 25 mM KCl

1% DMSO (from compound) 1 μM FAM-TSRHK(AC)KL-CONH2 5 nM HDAC Enzyme(specific activity may vary from lot-to-lot, and enzyme concentrationmay need to be adjusted to yield ˜10-20% conversion of substrate toproduct).

Substrate and product peptides present in each sample are separatedelectrophoretically using the LabChip 3000 capillary electrophoresisinstrument. As substrate and product peptides are separated, two peaksof fluorescence are observed. Change in the relative fluorescenceintensity of the substrate and product peaks is the parameter measured,reflecting enzyme activity. Capillary electrophoregramms (RDAacquisition files) are analyzed using HTS Well Analyzer software(Caliper Life Sciences). The enzyme activity in each sample isdetermined as the product to sum ratio (PSR): P/(S+P), where P is thepeak height of the product peptide and S is the peak height of thesubstrate peptide. For each compound, enzyme activity is measured atvarious concentrations (12 concentrations of compound spaced by 3×dilution intervals). Negative control samples (0%-inhibition in theabsence of inhibitor) and positive control samples (100%-inhibition, inthe presence of 20 mM EDTA) are assembled in replicates of four and areused to calculate %-inhibition values for each compound at eachconcentration. Percent inhibition (P_(inh)) is determined usingfollowing equation:P_(inh)=(PSR_(0%)−−PSR_(inh))/(PSR_(0%)−PSR_(100%))*100, where PSR_(inh)is the product sum ratio in the presence of inhibitor, PSR_(0%) is theaverage product sum ration in the absence of inhibitor and PSR_(100%) isthe average product sum ratio in 100%-inhibition control samples.

The IC50 values of inhibitors are determined by fitting the inhibitioncurves (P_(inh) versus inhibitor concentration) by 4 parameter sigmoidaldose-response model using XLfit 4 software (IBDS).

The results of this assay for certain compounds are reported in Table 2,below. In the table, “A” indicates a K_(d) value of less than 0.1 μM;“B” a K_(d) value of between 0.1 μM and 0.5 μM; “C” a K_(d) value ofgreater than 0.5 μM and less than or equal to 5.0 μM; and “D” a K_(d)value of greater than 5.0 μM.

TABLE 2 HDAC2 HDAC1 Compound IC50, IC50, No. (uM) (uM) 1 B B 2 C B 3 C B4 C B 5 C C 6 C C 7 C B 8 C B 9 C B 10 B B

HDAC2 Enzymatic Inhibition Assay in SH-SY5Y Cell Lysate

Cell Culture and Inhibitor Treatments

SH-SY5Y cells (Sigma) were cultured in Eagle's Modified Essential Mediumsupplemented with 10% fetal bovine serum and pen/strep. Twenty-fourhours prior to compound dosing 20 uL of cells were plated in white 384well plates at a density of 1,500 cells/well. Compounds were seriallydiluted in neat DMSO and then diluted 1:100 v/v into media without FBSand mixed. Media was removed from the plated cells and the dilutedcompounds in serum free media (1% v/v final DMSO) were added andincubated at 37.0 for five hours. Ten uL of HDAC-Glo 2 reagent with 0.1%Triton X-100 was then added, the plate was mixed and allowed to developat room temperature for 100 minutes. Plates were then read with aSpectramax LMax luminometer employing a 0.4 s integration time. Doseresponse curves were constructed with normalized data where CI-994 at100 uM was defined as 100% inhibition and DMSO alone as 0% inhibition.

The results of this assay for certain compounds are reported in Table 3,below. In the table, “A” indicates an IC₅₀ value of between 0.1 μM and 1μM; “B” indicates an a IC₅₀ value of between 1.0 μM and 1.5 μM; and “C”indicates an a IC₅₀ value of greater than 1.5 μm.

TABLE 3 HDAC2 IC50, Compound SH-SY5Y Cell No. Lysate (uM) 1 A 2 B 3 A 4B 5 B 6 C 7 A 8 A 9 A 10 A

Erythroid and Myeloid CFU Assay

Clonogenic progenitors of human erythroid (CFU-E, BFU-E),granulocyte-monocyte (CFU-GM) and multipotential (CFU-GEMM) lineageswere assessed in a semi-solid methylcellulose-based media formulationcontaining rhlL-3 (10 ng/mL), rhGM-SCF (10 ng/mL), rhSCF (50 ng/mL) andEpo (3 U/mL).

Cells

Normal human bone marrow light density cells derived from normal bonemarrow (NorCal Biologics, California) and qualified at ReachBio, werestored in the gaseous phase of liquid nitrogen (−152° C.) until requiredfor the assay. On the day of the experiment, the cells were thawedrapidly, the contents of each vial was diluted in 10 mL of Iscove'smodified Dulbecco's medium containing 10% fetal bovine serum (IMDM+10%FBS) and washed by centrifugation (approximately 1200 r.p.m. for 10minutes, room temperature). The supernatant was discarded and the cellpellets resuspended in a known volume of IMDM+10% FBS. A cell count (3%glacial acetic acid) and viability assessment (trypan blue exclusiontest) was performed for the bone marrow sample.

Compounds

On the day of the experiment, the compounds were dissolved in DMSO to astock concentration of 10 mM. Serial dilutions were prepared from thestock concentration to achieve concentrations of 2 and 0.4 mM. Whenadded to the methylcellulose-based media at 1:1000 (v/v), the final testconcentrations of 10, 2 and 0.4 μM were achieved. Additionally, 5-FU wasevaluated at 1.0, 0.1 and 0.01 μg/mL.

Method Summary

Clonogenic progenitors of the human erythroid (CFU-E and BFU-E) andmyeloid (CFU-GM) lineages were set up in the methylcellulose-based mediaformulations described above. All compounds were added to the medium togive the final desired concentrations (10, 2 and 0.4 μM). 5-Fluorouracil(Sigma Aldrich) was used as a positive control for progenitorproliferation (inhibition of colony growth) and was introduced to thehuman bone marrow cultures at 1.0, 0.1, and 0.01 μg/mL. Solvent controlcultures (containing no compound but 0.1% DMSO) as well as standardcontrols (containing no compound and no DMSO) were also initiated.

Human myeloid and erythroid progenitor assays were initiated at 2.0×10⁴cells per culture. Following 14 days in culture, myeloid and erythroidcolonies were assessed microscopically and scored by trained personnel.The colonies were divided into the following categories based on sizeand morphology: CFU-E, BFU-E, CFU-GM and CFU-GEMM.

Statistical Analyses of CFC Numbers

The mean±one standard deviation of three replicate cultures wascalculated for progenitors of each category (CFU-E, BFU-E, etc.).Two-tailed t-tests were performed to assess if there was a difference inthe number of colonies generated between solvent control and treatedcultures. Due to the potential subjectivity of colony enumeration, a pvalue of less than 0.01 is deemed significant. To calculate theconcentration of 50% inhibition of colony growth (IC₅₀) for eachcompound, a dose response curve was generated plotting the log of thecompound concentration versus the percentage of control colony growthusing XLfit software (IDBS). The concentration of 50% inhibition ofcolony growth (IC₅₀) was calculated based on the sigmoid curve fit usingDose-Response, One-Site Model formula: y=A+[(B−A)/(1+((C/x){circumflexover ( )}D))], where A=the initial value (baseline response), B=maximumresponse, C=center (drug concentration that provokes a response halfwaybetween A and B) and D=slope of the curve at midpoint. Further, plotsand additional dose response curves were generated using GraphPad Prism7.0.

Morphological Assessment of Colonies

Photographs were taken of representative hematopoieticprogenitor-derived colonies from various lineages, illustrating coloniesin the presence of the solvent control as well as colonies in thepresence of the test compounds.

Erythroid (CFU-E and BFU-E), myeloid (CFU-GM) and multi-potential(CFU-GEMM) colony enumeration was performed by trained personnel. Thedistribution of colony types as well as general colony and cellularmorphology was analyzed. For statistical analysis colony numbers incompound treated cultures were compared to the solvent control cultures.5-FU was used as a positive control for toxicity in these assays and theinhibitory effects obtained for this compound were exactly as expected.The experiment was used to evaluate the potential effect of testcompounds on human erythroid and myeloid progenitor proliferation in amethylcellulo se-based medium. The IC₅₀ values were calculated fromXLfit. Dose response curves for erythroid and myeloid toxicity generatedby XLfit. Finally, nonlinear regression curve fitting and IC₅₀ s±95% CI,were calculated by Prism 7.0.-GEMM.

Results are shown in Table 4.

TABLE 4 Erythroid % Myeloid % control control remaining @ remaining @Compound Structure 10 uM dose 10 uM dose Comparator 1

22 34 10

38 77 Comparator 2

45 103 3

89 109 Comparator 3

18 9 6

69 82 Comparator 4

28 39 8

72 75 Comparator 5

25.7 66.1 1

53 100 5

69 82 Comparator 6

22.9 58.9 9

87 102 Comparator 7

35 82 4

62 102 Comparator 8

33 70 2

62 92 Comparator 9

60 79 7

69 105

The contents of all references (including literature references, issuedpatents, published patent applications, and co-pending patentapplications) cited throughout this application are hereby expresslyincorporated herein in their entireties by reference. Unless otherwisedefined, all technical and scientific terms used herein are accorded themeaning commonly known to one with ordinary skill in the art.

1. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 2. A compositioncomprising a compound of claim 1, or a pharmaceutically acceptable saltthereof; and a pharmaceutically acceptable carrier.
 3. A method ofinhibiting HDAC activity in a subject comprising the step ofadministering to the subject in need thereof an effective amount of acompound of claim 1, or a pharmaceutically acceptable salt thereof.
 4. Amethod of treating a condition in a subject selected from a neurologicaldisorder, memory or cognitive function disorder or impairment,extinction learning disorder, fungal disease or infection, inflammatorydisease, hematological disease, psychiatric disorders, and neoplasticdisease, comprising administering to the subject in need thereof aneffective amount the compound of claim
 1. 5. The method of claim 4,wherein the condition is: a. a cognitive function disorder or impairmentassociated with Alzheimer's disease, Huntington's disease, seizureinduced memory loss, schizophrenia, Rubinstein Taybi syndrome, RettSyndrome, Fragile X, Lewy body dementia, vascular dementia,frontotemporal dementia, ADHD, dyslexia, bipolar disorder and social,cognitive and learning disorders associated with autism, traumatic headinjury, attention deficit disorder, anxiety disorder, conditioned fearresponse, panic disorder, obsessive compulsive disorder, posttraumaticstress disorder (PTSD), phobia, social anxiety disorder, substancedependence recovery, Age Associated Memory Impairment (AAMI), AgeRelated Cognitive Decline (ARCD), ataxia, or Parkinson's disease; or b.a hematological disease selected from acute myeloid leukemia, acutepromyelocytic leukemia, acute lymphoblastic leukemia, chronicmyelogenous leukemia, myelodysplastic syndromes, and sickle cell anemia;or c. a neoplastic disease; or d. an extinction learning disorderselected from fear extinction and post-traumatic stress disorder.
 6. Themethod of claim 5, wherein the condition is Alzheimer's disease,Huntington's disease, frontotemporal dementia, Freidreich's ataxia,post-traumatic stress disorder (PTSD), Parkinson's disease, or substancedependence recovery.